Solution mining of ore containing sodium carbonate and bicarbonate

摘要

A solution mining method for recovering alkali values from a cavity of an underground ore formation comprising trona and/or wegscheiderite; a manufacturing process using such method to make sodium-based product(s); and a sodium-based product obtained therefrom. The method comprises: an ore dissolution phase (a) in which the incongruent double-salt in trona and/or wegscheiderite is dissolved from an ore face in a first solvent, and a cavity cleaning phase (b) in which sodium bicarbonate deposited on the ore face during the dissolution phase (a) is dissolved into a second aqueous solvent having a higher pH, hydroxide content, and/or temperature and is partly or completely converted in situ to sodium carbonate. The method further comprises withdrawing a liquor resulting from either phase to the ground surface, optionally recycling some liquor to the cavity; and passing some liquor through a crystallizer, a reactor, and/or an electrodialyser, to form at least one sodium-based product which is recovered.

主权项

1. A method for recovering alkali values from at least one cavity of an underground ore formation, said ore comprising trona and/or wegscheiderite, said method comprising:
carrying out an ore dissolution phase (a) into the at least one cavity, said ore dissolution phase comprising dissolving in situ at least a portion of ore from an ore face of the cavity into a first aqueous solvent to form a first liquor comprising sodium carbonate and to deposit sodium bicarbonate on at least a portion of the ore face; carrying out a cavity cleaning phase (b) into the same cavity where the ore dissolution phase (a) takes place in order for at least a portion of said deposited sodium bicarbonate to be removed from the ore face, said cleaning phase (b) comprising dissolving in situ at least a portion of the deposited sodium bicarbonate and optionally dissolving in situ at least a portion of the ore from the ore face into a second aqueous solvent to form a second liquor comprising sodium carbonate, said second aqueous solvent having a parameter selected from the group consisting of pH, hydroxide concentration, temperature, and any combinations of two or more thereof, which has a higher value than the first aqueous solvent used in the dissolution phase (a); and repeating the ore dissolution phase (a).